CLASS 10 SCIENCE CHAPTER 5 PERIODIC CLASSIFICATION OF ELEMENTS EASY NOTES class-ten-notes-ch-five By LEARNING JUNCTION

                                                                        

ᒪEᗩᖇᑎIᑎG ᒍᑌᑎᑕTIOᑎ 

                                       CBSE

                                      CLASS 10 SCIENCE

                CHAPTER 5 PERIODIC CLASSIFICATION OF ELEMENTS

                                                 EASY NOTES

1. Development of the Periodic Table:

👉The periodic table is an arrangement of elements in a systematic manner based on their properties.

👉Dmitri Mendeleev, a Russian chemist, is credited with the development of the first periodic table in 1869.

👉He arranged the elements in increasing order of their atomic masses and observed periodicity in their properties.

👉The modern periodic table is based on the atomic number of elements.

2. Modern Periodic Law:

👉The modern periodic law states that the properties of elements are a periodic function of their atomic numbers.

👉Elements with similar properties are grouped together in the same vertical column called a group or family.

👉The period number indicates the highest energy level or shell of an element.

3. Periods and Groups:

👉The periodic table consists of seven horizontal rows called periods (1 to 7) and eighteen vertical columns called groups (1 to 18).

👉Elements in the same group have similar chemical properties because they have the same number of valence electrons.

👉The groups are further divided into subgroups: s-block, p-block, d-block, and f-block.

4. Classification of Elements:

👉The periodic table is divided into four blocks:

👉s-block: Groups 1 and 2 (except hydrogen) containing alkali metals and alkaline earth metals.

👉p-block: Groups 13 to 18 containing metals, non-metals, and metalloids.

👉d-block: Transition elements (transition metals) located in the middle of the periodic table.

👉f-block: Lanthanides and actinides placed separately at the bottom of the periodic table.

5. Trends in Periodic Properties:

👉Atomic size: Atomic radius decreases from left to right across a period and increases from top to bottom within a group.

👉Valency: Elements in the same group have the same valency due to the same number of valence electrons.

👉Metallic and non-metallic properties: Metals are located on the left side of the periodic table, while non-metals are on the right side.

👉Electronegativity: Electronegativity generally increases from left to right across a period.

👉Ionization energy: Ionization energy increases from left to right across a period and decreases from top to bottom within a group.

6. Modern Periodic Table:

👉The modern periodic table consists of 118 elements, arranged in order of increasing atomic number.

👉Elements are classified into metals, non-metals, and metalloids based on their properties.

👉The periodic table provides valuable information about the properties, electronic configuration, and relationships between elements.

⭐Remember to refer to your textbook and class notes for a more detailed understanding of the topic.